The invention relates to turbojet engines equipped with an afterburner and, more particularly, to such engines for propelling a missile. For this purpose the engine is expendable and therefore a low cost and lightweight engine is of prime importance.
A military aircraft missile generally is launched by a special launching mechanism either from the ground or from an airplane. Turbojet engines have been used to propel such missiles after launch to provide the cruise velocity. In addition, such turbojet engines for missiles have been provided with afterburners to increase the speed of the missile when the target area is approached in order to minimize the possibility of detection and/or interception of the missile. The addition of the afterburner necessitates providing the engine with a variable area exhaust nozzle having at least two positions, one for the non-afterburning mode of operation and one for the afterburning mode of operation.
In the past, such a variable-area-exhaust-nozzle turbojet engine not only required a relatively complex exhaust nozzle but also required a nozzle actuation mechanism for varying the exhaust nozzle area and also required a fuel control system that could be coordinated with the nozzle area. Such a configuration is relatively expensive and heavy and, therefore, is not acceptable for a low cost, expendable turbojet engine for a missile.